1. Field of the Invention
The invention relates to a method for stepwise bending of glass sheets in which the glass sheets heated to bending temperature are bent in stages into the final shape in a horizontal position. More particularly, it relates to a method for stepwise bending of glass sheets in which the glass sheets heated to bending temperature are bent in stages into the final shape in a horizontal position in at least two successive bending stations, are raised by suction in the last bending station by an upper convex bending mold provided with suction openings, and are transferred onto a moveable carrier ring. The invention also relates to devices for carrying out the method.
2. Description of the Related Art
Multistage bending methods employing stepwise pressing bending are advantageous for various reasons. In particular, such multistage bending methods can be used to produce complicated shapes of sheet, for example spherical bends, the production of which in a single-stage bending process is attended by difficulties.
A two-stage bending method and a device suitable for carrying out the method are disclosed, for example, in DE 4203751 C2. In this known bending method, the lower and upper bending molds are constructed as rigid pressing dies in the two bending stations, the upper bending molds in each case being full-area convex suction bending molds. The initially bent glass sheet is transferred by the first suction bending mold into the subsequent pressing bending station, while the suction bending mold of the second pressing bending station transports the finally bent glass sheet into a transfer station in which the glass sheet is transferred onto the support frame. The repeated gripping of the glass sheet during the bending process by the suction bending devices raises the risk that the glass surface is damaged by relative movements between the glass sheet and the suction bending devices.